The owner of Chelsea Football Club, Roman Abramovich, has told a court that claims he betrayed a Russian business rival are "wholly without merit".

Mr Abramovich is being sued for billions of pounds by exiled Russian oligarch Boris Berezovsky at the Commercial Court in London.

Mr Berezovsky, 65, claims Mr Abramovich "intimidated" him into selling shares for a fraction of their true worth.

Mr Abramovich, 45, denies alleged breaches of trust and contract.

Before he gave evidence, the court heard a written statement, which was given to the judge Mrs Justice Gloster.

In it, Mr Abramovich said he owed Mr Berezovsky nothing.

He said: "I would respectfully hope that it will be apparent to this court that Mr Berezovsky's claims are wholly without merit.

At the scene

By Sarah BellBBC News

Roman Abramovich faced a pack of photographers as he arrived for his day in the spotlight at the High Court.

Inside, the buzz of Russian accents could be heard as journalists scrambled for seats close to where the intensely private billionaire would take the stand.

The owner of Chelsea football club, who rarely speaks in public, looked relaxed when he arrived, watched by several minders.

Dressed in a navy suit and Chelsea-blue tie, Abramovich donned a pair of headphones in order to hear his translator.

Giving evidence in Russian, he was sparing with his softly spoken words as he responded to questioning from Lawrence Rabinowitz QC.

Despite the translator, Abramovich frequently said he did not understand what point the lawyer was trying to make or what he wanted him to say.

"Just give us a straight answer," Mr Rabinowitz asked in one combative exchange, as he asked the Russian to run through his background, and business partners.

"Mr Berezovsky has already obtained a very substantial sum of money from me, and I do not believe that he has any entitlement to be paid anything more, whether in law or honour."

'Political godfather'

The football club owner also gave evidence in the witness box, speaking in Russian and having his words translated into English. He was watched from across rows of lawyers by his opponent, Mr Berezovsky, who is hoping to win £3bn in damages for breach of contract.

He said he had served in the army and studied law after leaving school at 16, beginning his business career by selling plastic toys.

The BBC's Sarah Bell said that there was laughter in court when Mr Abramovich was pressed on whether one of his partners was, in his opinion, rich.

"It's hard for me to say whether someone is a wealthy person or not a wealthy person," he said.

He is expected to continue to be in the witness box for several days.

Mr Berezovsky alleges that billionaire Mr Abramovich "betrayed" him and intimidated him into selling shares in Russian oil company Sibneft for a "mere $1.3bn" (£800m).

He says this happened after he left Russia in 2000 following a falling-out with the then President Vladimir Putin.

Mr Abramovich denies the allegations and denies that Mr Berezovsky is entitled to damages.

He says Mr Berezovsky was paid millions of pounds for his services as a "political godfather" but was not a business partner.